JSFL - Dropbox, relative paths and library.updateItem()

Hi there, we have an issue in which content is shared in a dropbox folder between multiple users. However, due to the fact that Animate seems to use absolute paths, when UserA tries to open a file created by UserB, it's trying to open images linked to UserA dropbox account - rather than use relative paths and find it on their own dropbox folder.

I don't believe (please correct me if I'm wrong) you can change Animate to use relative paths, so one solution was to use the library.updateItem() function (eqivalent to properties/update on a file)  to repath the images, but this doesn't seem to be available via JSFL (it says 'updateItem is not a function').

So is there any way to resolve this?

Thanks for any help